Manufacture of sheet silicon alloy.



UNITED STATES PATENT OFFICE.

. OTTO GRAEF, OI BJISIIMIIABGKIH'lJTl-"JEE, GERMANX, ASSIGNOR TO THE FIRM OF BISMARCK- Hll'TTE, 0F BISMARCKH'UTTE, GERMANY.

MANUFACTURE OF SHEET SILICON ALLOY.

1% Drawing.

To all whom it may concern:

Be it known that I, O'r'ro GRAEF, subject of the Emperor of Germany, residing at Bismarckhiitte, Province of Silesia, Germany. have invented certain new and useful Improvements Silicon Alloy. specification.

This invention has for its object to improve the magnetic and mechanical properties of sheet metal alloyed with silicon.

According to the present invention, the sheets, in their otherwise finished state, are pickled in an acid solution and thereupon washed in a neutralizing solution and dried.

By pickling the sheets in this manner, after the final manufacture of the sheet silicon alloy, the properties of the sheets are considerably improved. In particular. the permeability is increased .and the loss due to hysteresis is reduced. Moreover the further advantage is obtained that the insulating paper, which is subsequently affixed to the sheets, adheres more firmly and does not become detached with the scale.

It is well known to anneal the sheet silicon alloy after manufacture in order to affect its properties but hitherto, "in order to prevent the troublesome peelin off of the paper with the scale resultin rom the manufacture of the sheets, it has een usual to manufacture sheets of this kind free from scale by pickling them, after manufacture, to remove the scale before subjecting-them to the necessary annealing process. The applicant has found however, that by proceeding in the reverse direction to that just described, that is, by first annealing the of which the following is a sheets and then finally pickling them, a con- Speclfication of Letters Patent.

in the Manufacture of Sheet siderable improvement in the quality of the. sheets is obtained as compared with the old method, both as regards the reduction of the loss in watts and the increase of the induction of the sheets.

In carrying out the improved method, the otherwise finished sheets, that is to say, the finally annealed sheets, are pickled in a warm dilute acid solution, being left to the action of the said solution for a length of time dependent on the strength of the acid bath. Thereupon the sheets are washed in a neutralizing solution and, after being again washed if required, are passed through heated rollers to dry the sheets.

Extensive use. of this process has absolntely demonstrated that by treating plates of high silicon content in the manner described the wattage loss is materially re- Patented Feb. 29, 1916. Application filed June 24, 1914. Serial No. 847,069.

duced and the plates rendered superior to a o'r'ro GRAEF.

Witnesses:

- LoUIs S. STAEL,

EaNEsr SCHMIDT. 

